Method of making slide fastener elements



NW. L 1949 A. GRAF 2,486,41

METHOD OF MAKING SLIDE FASTENER ELEMENTS 2 Sheets-Sheet 1 Filed July 50, 1947 INVENTOR F A R G A METHOD OF MAKING SLIDE EASTENER ELEMENTS Filed July 30, 1947 2 Sheets-Sheet 2 7%? .ST/lT/(WB m 2 a m w m 7 I 6 J 4 \MM 6 a .J 2 I n 4 w I. 1

m w m $1 M Mv ATTORNEYS Patented Nov. 1, 1949 orrlcs METHOD OF MAKING SLIDE FASTENEB ELEMENTS Arthur Grai', Far Rockaway, N. Y.

Application July 80, 1947, Serial No. 764,646

3 Claims. (Cl. 29-148) This invention relates to the manufacture of slide fastener elements.

In the manufacture of slide fastener elements, that is the interlocking elements which are attached to the edges of flexible tapes, it is of importance that manufacture be accomplished with a minimum of waste metal; and it is also important that the side walls of the individual elements be smooth to the touch and free from burrs to insure easy operation of the slider which interlocks and separates the elements in use.

It is a presently accepted practice to manufacture the elements and to amx them to their supporting tapes in a continuous process, the blank metal being fed into the machine as a continuous tape or strip which is operated upon by blank ing and cutting .dies to form the head and leg portions of the individual elements. Insofar as I am aware, most prior art manufacturing methods cut the side edges of the metal strip in the formation of the leg portions, with the result that the edges become roughened and the completed tape with its thereon positioned elements must be passed between brushes or the like in order to remove the ragged or rough outer edges. This additional manufacturing step does not always completely remove the roughness and further inspection is required before the product may be released for shipment to the purchaser.

In the manufacture of slide fasteners in which a continuous strip of metal is fed through the successive blanking and forming operations and eventuall severed for attachment of the individual units to the supporting tape, it has been difficult to control accurately the respective elements at their various stages of formation so as to achieve accurate positioning of the partially formed elements at the several manufacturing stages, and proper spacing of the completed elements on the tape.

It is an object of the present invention to manufacture slide fastener elements by means which do not require punching or cutting the side edges of the strip stock, so that said edges will at all times retain their original smoothness and make is unnecessary to brush or polish the completed structure.

It is yet another object of the invention to provide an improved method of making slide fastener elements in which successive, partially-formed elements are inter-linked, chain-fashion, to accurately maintain the position of the elements with respect to each other during passage through the various manufacturing operations.

It is also an object of the invention to manufacdure affords flexibility of the strip stock which is not present in prior art methods.

It is a further object of the invention to pro- V vide a method of manufacturing slide fastener elements in which the side walls are curved, thereby making them smooth to the touch and freely operable in association with the conventional slider member.

Another object of the invention is to provide an improved method of manufacturing slide fastener elements whereby waste of material and steps of procedure are reduced to a minimum and dies and tools which are simpler and less expensive may be employed.

Other features and advantages of the invention will be apparent from the following detailed description of presently preferred methods of manufacture.

In the accompanying drawings, which are on an enlarged scale, Fig. 1 is a somewhat schematic top plan view of one method of manufacturing pursuant to the present invention, showing the stages of manufacture from initial strip stock to ultimate attachment to the carrying tape.

Fig. 2 is a vertical sectional elevation taken on lines 2-2 of Fig. l and illustrating more clearly the respective operating steps.

Fig. 3 is an end elevation in sections on lines 3-3 of Fig. 2 showing the step of removing the Waste stock and spreading the jaws of the slide fastener elements.

Fig. 4 is a perspective of a portion of the strip stock showing elements in partial formation.

Fig. 5 is a plan view of a portion of the strip of partially-formed elements independent of the forming equipment.

Fig. 6 is a plan view of a portion of a series of partially formed elements, similar to Fig. 5, but resulting from a slightly different manufacturing process.

Figs. 7 and 8 are figures similar to Figs. 1 and 2, showing another manufacturing process; and

Fig. 9 is a perspective similar to Fig. 4 illustrating interconnected, partially formed elements pursuant to the Fig. 7 manufacturing process.

Referring to the drawings, a strip ll), of deformable material, preferably metal, has a width and thickness equal to the ultimate width as thickness of the completed element. Preferably the strip has rounded side walls as appears from Fig. 3. The strip is fed between the die bed II and stripper plate l2 of the press, and at station A is acted upon by upper and lower reciprocating dies l3 and I4. Die l3 has a projection l5, which forms a preferably circular dimple l6 in the strip. Inasmuch as die l4 has a plane surface immediately beneath the projection I5, said projection will swage the strip 10 and expand it outwardly into an approximately circular shape without materially deforming the curved side walls of the strip.

The formation of the swaged portion is controlled by the side stops or punches l1, l8, which maintain the parallel side walls IQ, of the ultimate head portions and form notches 28 which define the side wall corners of the heads.

Punches l3 and M are also formed to provide the tip 2| and opposite socket 22 which cause the head portions of completed fasteners to interlock, as is well known.

The strip stock is then advanced between the die bed and stripper plate to station B, at which point a shearing tool 23 acts on the strip against a die opening similar in shape to the contour of the punch. This operation shears the strip to form a partially shaped element 25 having jawforming walls 26, 26a which embrace a head 21 at the end of a neck 28 extending integrally'from the next succeeding partially shaped element 29. The punch 23 also shears the strip at lines 30 which extend from the corners 20 to the neck 28 and outline the head 3| of the elements. A pressure pad 24 reciprocates within the die opening and opposes the punch 23. As the punch drives downwardly, the pressure pad moves in the same direction and supports the head and neck 2?, 28. At the upward stroke of the punch, the pressure pad pushes parts 21, 28, and with them, the whole strip, upwardly against the stripper plate l2. It thus lifts the strip above the projection on die M which provides the socket 22, and the strip is free to advance to the next station, die l3 being timed to retract to clear the strip. It will be understood that upper movement of the pressure pad is limited, and it therefore does not interfere with the forward movement of the strip.

Punch 23 may, but preferably does not, completely shear the strip stock, leaving, as shown in Fig. 2 a thin membrane 32 at the end of the down stroke. The pressure pad 24, driving the stock upwardly against the stripper plate l2, severs the membranes 32 left by the partial shear of punch 23, and returns the members 21, 28 back within the strip stock. Adjacent partially formed ele-' ments, such as 25, 29, and 33, see Fig. 4, are therefore physically independent, but are interlinked by a key defined by the head 21 and neck 28. The partially formed elements are interlocked for accurately registering passage through the remaining operations.

An important practical advantage resulting from the swaging of the stock into the arcuate wall shape is that such shape permits the use of the relatively easily formed circular cutting portion 34 of the punch 23 while insuring adequate width of the jaw elements 26, 26a.

At station C the head 21 and neck 28 are cut away from a partially-formed element 45 by being struck downwardly by the tapered cut-off and spreading punch 36, which cuts the neck 28 across its base, and spreads the jaws 26, 26a of the im mediately preceding element 35. The laws are spread outwardly by the lower taper end of punch 36 (see Fig. 3) It will be understood that the jaws are thin, and must be supported against being bent downwardly during the spreading operation. There are therefore provided the sidewardly movable members 31, 38, which support the jaws 26, 26a when being spread. Said members close upon retraction of the punch and act to strip the waste, as represented by head 21 and neck 28, from the bottom of the punch.

At station D the element 45 has been advanced by the progression of its preceding element 35 so that its spread jaws embrace the beaded edge 4| of tape 42 before the neck 28 has been severed and the jaws of the element 35 closed. Plungers 43, 44 compress said jaws tightly about the tape and straighten the outer side walls, as shown. Such roughness as appears on the inner walls of the jaws improves the grip of the element on the tape. The operation at station D is preferably so timed with respect to station C that the jaws are clamped about the tape coincidentally with, or just prior to, the severance of the neck 28.

Fig. 5 shows a portion of the strip of partially formed elements independent of the forming equipment, to show how the spread-jaw element 35 will be brought into station D as the preceding element 33 is advanced to station C. Therefore, although the respective elements have been physically separated from each other at an early stage of manufacture, they are mutually articulated for accurate positioned movement, as a relatively flexible chain, through the respective operations.

In the form shown in Fig. 6, the manufacturing steps are similar to the above with certain important exceptions. The strip in at station A is not swaged to produce the circular wall structures, and hence the dimple iii of the Fig. 5 embodiment is not present. The station A punch forms the tip 21 and cavity 22 for the interlocking head, and cuts the sidewalls to provide the notches 50 which deflne the side-wall corners of the final head shape.

At station B the element is operated on by a punch and pressure pad (not shown) which are similar in operation to punch 23 and pressure pad 26, but conflgurated to provide a tear-dropshaped head 5i extending from a neck portion 52, the teardrop shape being desirable to leave jaw stock 53, 54 of adequate width. The lines of severance 55, 56 result .from the rebound of the pressure pad. At station 0 the head and neck 5!, 52 of one element are removed by an appropriately shaped punch, and the jaws 53, 54 of the immediately preceding element are spread. At station D the jaws of one element are clamped about the beading 4| on tape 42 and the manufacturing steps are completed.

In the manufacturing method shown in Figs. '7 and 8, the steps at station A are the same as in Fig. 1. At station B, the punch 60 and pressure pad 6| are designed to operate on the side walls 62, 63, and hence the punch 60 has a circular cavity 64 and an entrance slot 65. Said punch is also formed with faces to form the arcuate cuts 66, 61 when the pressure pad rebounds to break the membrane resulting from partial penetration of the punch.

Punch 60 and pressure pad 6| are similar in contour and slide freely vertically within the die opening. Punch 60- is relieved or tapered, as shown, to avoid striking the tip 2|, and pressure pad 6| is shaped to accommodate the downward bending of the stock at the time of shear. The pressure pad lifts the strip in the area of the shear line to enable the strip to move forward to the next station. Fig. 9 is a perspective of the strip showing the element a in its downwardly d flected position. The figure shows that the sides of the strip stock have been moved downwardly with respect to the head 21 and neck 28 extending integrally from element 29.

Following station B, therefore, the partially formed elements are in fact severed from the initial stock, but are mechanically keyed together. At station C the keying member is punched out and the jaws spread; and at station D the element is attached to the tape.

It will be seen, therefore, that although the individual elements are severed from the strip stock before reaching the tape, therefore eliminating the trouble-causing step of cutting the element from the strip after attaching to the tape, the method described herein maintains the exact registry of partially-formed elements during the intermediate manufacturing stages, and brings the finally shaped element into accurate register with the tape at the attachment operation. The spread jaws of one element straddle the beaded edge of the tape while the element is still interlinked with its preceding element. The interlinkage of the respective elements accurately controls the position of each element at the successive operating stations. It is understood, of course, that the strip I0 is acted upon by suitably timed feeding means (not shown) as is conventional in the art.

Thus, among others, the several objects of the invention as afore noted are achieved. Obviously numerous changes in construction and rearrangement of the parts might be resorted to without departing from the spirit of the invention as defined by the claims.

I claim:

1. The method of making slide fastener elements of the interlocking type which have a head portion, and jaw members which embrace a supporting tape, which includes the steps of operating on a continuous fiat strip of deformable metal to dimple the strip at a point intermediate the side edges thereof to cause an outward flow of material in the area of the ultimate jaw members; forming the tip and cavity of the ultimate head portion; severing one partially-formed element from a next succeeding one by cutting said material along an irregular line defining a neck extending from one element and terminating in a head portion concentric with and larger than the aforesaid dimple the neck being of less width than the width of the beaded edge of the supporting tape, whereby to form jaw portions on one element embracing said neck and head portlon; subsequently removing the neck and head portion of one element while spreading the jaw members of the immediately preceding element; and clamping the said jaw members about a supporting tape.

2. The method of making slide fastener elements of the type which have interlocking head portions, and Jaw members which embrace a supporting tape, which includes the steps of dimpllng a fiat strip of deformable metal centrally of its side edges to cause sideward flow to increase the width of the strip in the area of the ultimate jaw portions; severing one partiallyformed element from its preceding one by cutting through said material along a continuous line of severance which defines a head which includes the said dimpled portion and a neck extending therefrom and integral with the first-named partiallyformed element, said line of severance defining the inner edge of the jaw members of the said preceding elements said jaw members embracing said neck and head portion and said neck being of less width than the width of the beaded edge of the supporting tape; advancing the thus severed but interlinked elements to a succeeding station at which the said head and neck are severed from the one element and the jaw members of the preceding element are spread outwardly; advancing the last named element into juxtaposition with a tape; and clamping the said jaw members about said tape substantially coincidentally with the step of severing the said neck.

3. The method of making slide fastener elements of the type which have interlocking head portions, and jaw members which embrace a supporting tape, which includes the steps of dimpling a fiat strip of deformable metal centrally of its side edges to cause sideward flow to increase the width of the strip in the area of the ultimate jaw portions; severing one partially-formed element from its preceding one by cutting through said material along a continuous line of severance which defines a, head which includes the said dimpled portion and a neck extending therefrom and integral with the first-named partiallyformed element, said line of severance defining the inner edge of the jaw members of the said preceding elements said jaw members embracing said neck and head portion and said neck being of less width than the width of the beaded edge of the supporting tape; advancing the thus severed but interlinked elements to a succeeding station at which the said head and neck are severed from the one element and the jaw members of the preceding element are spread outwardly while being supported against deflection in a vertical plane; advancing the last named element into juxtaposition with a tape; and clamping the said jaw members about said tape substantially coincidentally with the step of severing the said neck.

ARTHUR GRAF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,331,884 Sundback Feb. 24, 1920 2,116,712 Prentice May 10, 1938 2,169,176 Poux Aug. 8, 1939 2,201,068 Wintritz May 11, 1940 2,221,740 Ulrich Nov. 12, 1940 2,245,031 Gottlieb June 10, 1941 2,335,626 Wintress Nov. 30, 1943 2,370,380 Ulrich Feb. 27, 1945 FOREIGN PATENTS Number Country Date 340,548 taly May 20, 1936 

